Aggregate UDFs

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jefftyzzer - 24 Jul 2006 23:36 GMT

The current issue of "Oracle Magazine" has an article on creating
custom aggregate functions, which naturally got me thinking about how
to do this in DB2.

I found some articles on creating custom aggregate functions in DB2,
written close to three years ago by Knut Stolze:

http://www-128.ibm.com/developerworks/db2/library/techarticle/0309stolze/0309sto
lze.html

Mr. Stolze says in the first article that "[c]urrently, there is no
direct way to implement your own user-defined aggregate function." I'm
wondering if this still represents the state-of-the-art, or if there is
now (or will be in V9) a non-Java way to do it.

--Jeff

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Serge Rielau - 25 Jul 2006 01:26 GMT

> The current issue of "Oracle Magazine" has an article on creating
> custom aggregate functions, which naturally got me thinking about how
[quoted text clipped - 9 lines]
> wondering if this still represents the state-of-the-art, or if there is
> now (or will be in V9) a non-Java way to do it.

Yes, C :-)

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Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ondemandbusiness/conf2006/

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jefftyzzer - 25 Jul 2006 02:23 GMT

Ouch! :-)

Although I think I now know the answer, allow me to rephrase for the
literal-minded: Is there now or is there planned native support for
user-defined aggregate functions?

--Jeff

> > The current issue of "Oracle Magazine" has an article on creating
> > custom aggregate functions, which naturally got me thinking about how
[quoted text clipped - 18 lines]
> IOD Conference
> http://www.ibm.com/software/data/ondemandbusiness/conf2006/

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Serge Rielau - 25 Jul 2006 04:16 GMT

> Ouch! :-)
>
> Although I think I now know the answer, allow me to rephrase for the
> literal-minded: Is there now or is there planned native support for
> user-defined aggregate functions?

There is no existing "native" support for user defined aggregates in DB2
including DB2 9. W.r.t. to plans you'll have to wait for either product
announcements or get yourself a non disclosure agreement.
The IBM DBMS which presently has user defined aggregates, and has had it
for years, is Informix IDS.
Are there any specific aggregates you're looking for?

Cheers
Serge

Signature

Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ondemandbusiness/conf2006/

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jefftyzzer - 25 Jul 2006 19:12 GMT

I'm not looking for any specific aggregate functions, I just thought
(think) it's a very cool capability (native or otherwise) and wanted to
look at it further. Thanks also for the reminder on Informix's
capabilities--I worked there back in the Finnochio/Dex/Stonebraker
days, and am heartened by IBM's continued support for--and development
on--the product.

--Jeff

> > Ouch! :-)
> >
[quoted text clipped - 17 lines]
> IOD Conference
> http://www.ibm.com/software/data/ondemandbusiness/conf2006/

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Serge Rielau - 25 Jul 2006 20:13 GMT

> I'm not looking for any specific aggregate functions, I just thought
> (think) it's a very cool capability (native or otherwise) and wanted to
> look at it further. Thanks also for the reminder on Informix's
> capabilities--I worked there back in the Finnochio/Dex/Stonebraker
> days, and am heartened by IBM's continued support for--and development
> on--the product.

No contest on the usefulness of the feature. :-)

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Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ondemandbusiness/conf2006/

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Knut Stolze - 25 Jul 2006 09:01 GMT

> Ouch! :-)
>
> Although I think I now know the answer, allow me to rephrase for the
> literal-minded: Is there now or is there planned native support for
> user-defined aggregate functions?

Now (or V9): not that I'm aware of.
Planned: yes.

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Knut Stolze
DB2 Information Integration Development
IBM Germany

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Knut Stolze - 25 Jul 2006 14:53 GMT

> Planned: yes.

Let me rephrase that: it is a known requirement and the DB2 developers are
thinking about implementing it.

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Knut Stolze
DB2 Information Integration Development
IBM Germany

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Knut Stolze - 25 Jul 2006 09:51 GMT

>> Mr. Stolze says in the first article that "[c]urrently, there is no
>> direct way to implement your own user-defined aggregate function." I'm
>> wondering if this still represents the state-of-the-art, or if there is
>> now (or will be in V9) a non-Java way to do it.
>
> Yes, C :-)

Actually, this aggregation stuff was originally developed in C. I ported it
to Java for the article to make it a bit simpler. Otherwise, I would have
had to explain shared memory etc.

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Knut Stolze
DB2 Information Integration Development
IBM Germany

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